Spin-correlation parameterAnn(θ/emph>) forn-pelastic scattering at 790 MeV

The spin-correlation parameter $A_{\mathrm{nn}}$ for free n-p elastic scattering has been measured for the first time for incident-neutron-beam energy $E_n$=790 MeV and c.m. angles 48°≤${\theta }^{\mathrm{*}}$≤149°. The data are compared with the widely differing predictions of several phase-shift analyses, clearly favoring one of them. They also are compared with recently published quasifree $A_{\mathrm{nn}}$ data for the more limited c.m. angular region 98°≲${\theta }^{\mathrm{*}}$≲122°.